1. Field of the Invention
The present invention relates to a small-size engine having a forced air cooling system for cooling a cylinder block and a cylinder head with a cooling air induced by a cooling fan.
2. Description of the Prior Art
A small-size engine having a forced air cooling system is known in which a cylinder block of an engine body has a longitudinal axis inclined relative to a horizontal direction and also to a vertical direction, and in which a fan housing is provided on one side of the engine body to cover a cooling fan mounted on one end of a crankshaft so that a cooling air induced by the cooling fan can be guided through the fan housing towards the cylinder block and a cylinder head of the engine body. In such arrangement, an air cleaner and a carburetor defining an air intake passage of the engine are mounted so as to protrude outwardly of the fan housing to secure a cooling air passage within the fan housing. See, for example, the Japanese Laid-open Patent Publication No. 10-227214. In this engine, in order to avoid interference between the carburetor and an ignition unit that is disposed at a location level with the carburetor and offset from the carburetor towards a longitudinal axis of a crankshaft, the air cleaner and the carburetor are so disposed as to protrude diagonally outwardly relative to the longitudinal axis of the crankshaft to thereby separate them away from the longitudinal axis of the crankshaft.
However, it has been found that since in the engine of the structure described above the air cleaner and the carburetor protrude a substantial amount outwardly from the engine body, the space required for an installation of the engine to various work units has been limited. Also, the engine operation tends to be irregular when the carburetor is strongly affected by an external heat, for example, radiant heat generated from the work unit.